PA28 pilot IFR at 2;500 feet reports NMAC with VFR traffic while attempting to cancel IFR and proceed visually for landing. Radio problems caused distraction during the incident.

Narrative

I was on an IFR flight plan now in VMC conditions. TRACON had me descend to 2;500 FT MSL. While descending I tried to cancel IFR as I had my home airport insight. However; TRACON did not respond to my cancellation. As I was leveling off at 2;500 FT and six miles away from my airport; TRACON advised of an aircraft at my 12 o'clock; coming at me. I broke right and descended as the conflicting aircraft passed by; doing a roll. TRACON was calling me again about the traffic. I was trying to answer but it appeared that TRACON could not hear me. At this point I realized that I was now at 2;100 FT MSL and made a climb back up to 2;500 FT and also switched to another radio. During the climb TRACON asked if I could hear them to IDENT; which I did. I was now back up to 2;500 FT and TRACON acknowledged my IDENT. I again said that I wanted to cancel IFR; to which he questioned my wanting to cancel. I told him [again] that I did want to cancel. TRACON had me squawk 1200 and I checked frequency. It appears that the location and altitude that I was at; I cannot use my #2 radio to talk to TRACON. I should use #1 instead. In the future when in VMC; I will cancel IFR much sooner to get out of the system so that I may devote my attention to my approach into my home airport.